The present invention relates to a computer for calculating the similarity between at least two patterns.
The pattern to which the similarity computer is applicable may be a voice pattern, one or more printed or handwritten letters and/or figures, or any other patterns. See Sakoe et al, U.S. Pat. No. 3,816,722 issued June 11, 1974, entitled "Computer for Calculating the Similarity between Patterns and Pattern Recognition System Comprising the Similarity Computer".
In connection with a voice pattern, in particular, recognition of input voice information is carried out by comparing a feature vector formed by the input voice information and a reference pattern. This kind of comparison between the two patterns is, conventionally, performed by a matching method using a time warping method of dynamic programming to obtain the calculation of an extremum. This conventional pattern matching method can be considered to provide matching by modifying patterns with reference to their similarity through addition or removal of feature vectors.
The respective patterns have particular feature vectors which, inevitably, vary from one another owing to variations in time when each of these vectors is extracted or to a variation in voice sources. Such variation components may be great even if the matching takes place in connection with patterns belonging to the same category. These variations result in erroneous pattern recognition.
Therefore, it is desired to reduce the variable components of the feature vectors as much as possible.